[llvm] r288374 - [SystemZ] Fix applyFixup for 12-bit fixups

[Ulrich Weigand via llvm-commits]

Author: uweigand
Date: Thu Dec  1 11:10:27 2016
New Revision: 288374

URL: http://llvm.org/viewvc/llvm-project?rev=288374&view=rev
Log:
[SystemZ] Fix applyFixup for 12-bit fixups

Now that we have fixups that only fill parts of a byte, it turns
out we have to mask off the bits outside the fixup area when
applying them.  Failing to do so caused invalid object code to
be emitted for bprp with a negative 12-bit displacement.


Modified:
    llvm/trunk/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp

Modified: llvm/trunk/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp?rev=288374&r1=288373&r2=288374&view=diff
==============================================================================
--- llvm/trunk/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp (original)
+++ llvm/trunk/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp Thu Dec  1 11:10:27 2016
@@ -94,12 +94,14 @@ void SystemZMCAsmBackend::applyFixup(con
                                      bool IsPCRel) const {
   MCFixupKind Kind = Fixup.getKind();
   unsigned Offset = Fixup.getOffset();
-  unsigned Size = (getFixupKindInfo(Kind).TargetSize + 7) / 8;
+  unsigned BitSize = getFixupKindInfo(Kind).TargetSize;
+  unsigned Size = (BitSize + 7) / 8;
 
   assert(Offset + Size <= DataSize && "Invalid fixup offset!");
 
   // Big-endian insertion of Size bytes.
   Value = extractBitsForFixup(Kind, Value);
+  Value &= ((uint64_t)1 << BitSize) - 1;
   unsigned ShiftValue = (Size * 8) - 8;
   for (unsigned I = 0; I != Size; ++I) {
     Data[Offset + I] |= uint8_t(Value >> ShiftValue);